JEE Main 2021 · 26 February · evening · Single correct · +4 / −1
Match List - I with List - II.
Choose the correct answer from the options given below :
| List - I | List - II | ||
|---|---|---|---|
| (a) | Sucrose | (i) | β-D-Galactose and β-D-Glucose |
| (b) | Lactose | (ii) | α-D-Glucose and β-D-Fructose |
| (c) | Maltose | (iii) | α-D-Glucose and α-D-Glucose |
- (a) (a) → (iii), (b) → (ii), (c) → (i)
- (b) (a) → (i), (b) → (iii), (c) → (ii)
- (c) (a) → (ii), (b) → (i), (c) → (iii)
- (d) (a) → (iii), (b) → (i), (c) → (ii)
Answer and solution
Answer (c) (a) → (ii), (b) → (i), (c) → (iii)
Solution
Chemistry ma’am · 4 steps
Look for the unusual sugar in each pair: fructose means sucrose, galactose means lactose.
- Sucrose. Cane sugar is made of α-D-glucose and β-D-fructose, joined C1 of glucose to C2 of fructose. It is the only one of the three that contains fructose, so (a) goes with (ii).
- Lactose. Milk sugar is made of β-D-galactose and β-D-glucose, joined by a C1 to C4 glycosidic link. It is the only one with galactose, so (b) goes with (i).
- Maltose. Malt sugar is two α-D-glucose units joined C1 to C4. So (c) goes with (iii).
- So. The matching is (a) → (ii), (b) → (i), (c) → (iii), which is option (c).
The idea to keep. Learn each disaccharide by its parts: sucrose is glucose + fructose, lactose is galactose + glucose, maltose is glucose + glucose. Spot the unusual monomer and the match falls into place.
Answer from the NTA final answer key. Solution by PrepWiser.